Roller drive for non-magnetic recording tape magnetically actuated



HORNA 3,318,502

0. ROLLER DRIVE FOR NON-MAGNETIC RECORDING APE MAGNETICALLY ACTUATED May9, 1967 Filed July 6, 1965 2 Sheets-Sheet 1 Q 2 2 8 2 Q 5w I 6 INVENTOR.

May 9, 1967 o HORNA 3,318,502

ROLLER DRIVE FOR NON-MAGNETIC RECORDING TAPE MAGNETICALLY ACTUATED FiledJuly 6, 1965 2 Sheets-Sheet 2 INVENTOR.

flfaA ar f/orna BY MAM W United States Patent Ofitice 3,318,502 PatentedMay 9, 1967 3,318,502 ROLLER DRIVE FOR NON-MAGNETIC RECORD- ING TAPEMAGNETICALLY ACTUATED Otakar Horna, Prague, Czechoslovakia, assiguor toVyzkumny ustav matematickych stroju, Prague, Czechoslovakia Filed July6, 1965, Ser. No. 469,442 Claims priority, application Czechoslovakia,July 17, 1964, 4,165/ 64 9 Claims. (Cl. 226180) This invention relatesto roller drives, and particularly to a roller drive for non-magneticrecording tape, such as punched or otherwise perforated tape in whichthe perforations constitute a record of information.

Precise and rapid reading of recording tape of the type describedrequires the tape to be stationary during readout, to be accelerated tofull traveling speed within a microsecond or less, and again to be fullyarrested within a similar period for the next reading. It is known todrive such tape by means of two rollers which engage the tapetherebetween.

The invention aims at providing a tape drive which employs drive rollersin the generally known manner, but which achieves the required high rateof acceleration and deceleration of the tape in a simple manner at lowinitial cost for the construction of the apparatus, and at low operatingcost.

A more specific object of the invention is the provision of a rollerdrive of the type described in which the rollers are moved toward andaway from each other by magnetic forces, and in which the air gaps inthe necessary magnetic circuit, and the reluctance of the circuit areheld to a minimum, thus requiring relatively little power for energizingthe circuit.

Another object is the provision of a roller drive in which the tapeengaging rollers may be selected as large in diameter as may be desiredwithout unduly increasing the power requirements of the drive by theenergy necessary for accelerating and decelerating the rollers.

A concomitant object is the provision of a roller drive whose rollersmay be chosen of relatively large diameter to minimize wear and otherdamage to the recording tape, particularly its splices, yet withoutunfavorably affecting the economy of the drive arrangement.

Yet another object is the provision of a roller drive whose motor neednot be substantially more powerful than is necessary for acceleratingthe small mass of the recording tape to be conveyed.

With these and other objects in View, the invention in one of itsaspects resides in a drive roller assembly and a pressure rollerassembly which are mounted on a common support in respective bearingsfor rotation about corresponding axes which may be moved relative toeach other as is conventional in roller drives.

Each roller assembly has three portions. One is the journal portionreceived in the associated hearing. A second portion has an exposedcontact face about the axis, and there is a third portion. The threeportions are axially spaced from each other, and one of the rollerassemblies, which may be either the drive roller assembly or thepressure roller assembly, has yet a fourth axial portion which isinterposed between the second and third portions and is enveloped by aconductive coil. A magnetic circuit which includes the gap between thecontact faces is closed between the third portions of the two rollers bya magnetizable member. The drive roller is driven in the usual manner.

Other features and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood fromthe following detailed description of preferred embodiments whenconsidered with the attached drawing in which:

FIG. 1 shows a roller drive of the invention in elevational section; and

FIG. 2 shows a modified roller drive in a view similar to that of FIG.1.

Referring now to the drawing, and initially to FIG. 1, there is seen anelectric motor I mounted on a supporting frame 4 in a manner not shownin detail, only a small portion of the frame being illustrated in thedrawing. The frame 4 consists of bronze or other nonmagnetic material.The output shaft 6 of the motor 1 is journaled in a bearing provided inthe frame 4, and its free end carries a cylindrical drive roller 7 and aflat annular rubber disc 10. The axial portion of the shaft 6 betweenthe bearing and the motor 1 carries a heavy flywheel 2. A magnet coil 3is fixedly mounted on the frame 4 coaxially with the shaft 6 andenvelopes a portion of the shaft 6 between the flywheel 2 and thebearing in the frame 4.

A bronze bearing 8 is pivotally mounted on the frame 4 for angularmovement in a plane which includes the axis of the shaft 6. A helicaltension spring 11 tends to pivot the bearing 8 counterclockwise, asviewed in FIG. 1, so that a cylindrical pressure roller 9 which isjournaled in the bearing 8 is held in abutting engagement with therubber'disc 10 by the tension of the spring 111. In the illustratedinoperative position of the apparatus, a gap is formed betweenrespective contact faces on the drive roller 7 and on a correspondingradially aligned portion of the pressure roller 9, and is wide enough toaccommodate a tape 5 with ample clearance, the tape being shown intransverse section.

The radial spacing of the axes of the rollers 7, 9 is such that the axisof the pressure roller 9 intersects the radial face of the flywheel 2 inall positionsof the apparatus. The frame 4 is provided with a largeopening for passage of the pressure roller 9 to facilitate assembly andmaintenance work, but the angular movement of the pressure roller 9during operation of the apparatus is limited to a few degrees. The gapbetween the end face of the pressure roller 9 and the radial flywheelface is therefore very small.

The roller drive illustrated in FIG. 1 is operated as follows:

The drive roller 7 is rotated at uniform speed by the motor 1. Thepressure roller 9 is rotated at a similar speed by its frictionalengagement with the edge of the rubber disc 4. The motor 1 need not bemuch more powerful than necessary to overcome bearing friction and thelike. Rotary energy is stored in the flywheel 2 while the drive is inthe illustrated position.

When it is desired to actuate movement of the tape 5, the coil 3 isenergized, thereby producing a magnetic circuit in the shaft 6, thedrive roller 7, the pressure roller 9 and the flywheel 2, all of whichare made of ferrous material such as solid or laminated iron, and aremagnetizable. The magnetic circuit is indicated by a broken line andarrows.

The pressure roller 9 is drawn to the drive roller 7, and the tape 5 isgripped between the rollers. The small amount of energy required foraccelerating the tape is derived to a small part from the pressureroller 9 which slows down as the rubber disc 10 is compressed by themagnetic attraction between the rollers, and mainly from the flywheel 2.Tape movement starts practically instantaneously at full speed.

The magnetic flux passes axially through the shaft 6 and through most ofthe roller 7 and the roller 9, and is mainly radial in the flywheel 2.There is no magnetic interaction between the shaft 6, the pressureroller 9 and the bearings in which the journal portions of the shaft andof the roller are received. Bearing friction is not affected by amagnetic field.

The diameters of the rollers 7, 9 may be selected large enough tominimize tape wear and the danger of breaking the tape during passage ofsplices between the rollers. The resulting relatively great Weight ofthe rollers is beneficial in the drive arrangement of the invention.

Relatively large tolerances are permissible in the construction of thedrive arrangement since dimensions are not overly critical, not even inthe bearing 8. The reluctance of the gap between the pressure roller 9and the flywheel 2 may be held to a minimum by placing the roller 9axially close to the flywheel, but also by making the radial end face oftheroller 9 very large as compared to the spacing between that face andthe opposite radial face of the flywheel.

It will be appreciated that the shaft 6 and the pressure roller 9, areaxially secured in their respective hearings in a convenitonal manner,but the necessary axial securing means have not been shown for the sakeof clarity.

Many modifications may be made in the roller drive illustrated in FIG. 1without departing from the scope of this invention, and FIG. 2 is merelyillustrative of such modifications.

The motor 1 of the modified embodiment of the invention is provided withan output shaft 16 which is in circumferential frictional engagementwith a flange on the flywheel 2. The shaft 6' which supports theflywheel is journaled in a sleeve bearing 12 fixedly attached to theframe 4. The free end portion of the shaft 6' carries the drive roller 7and the disc as described hereinabove with reference to FIG. 1. Thejournal portion of the drive roller 9 is received in the pivotallymounted bearing 8 and is urged into engagement with the rubber disc 10by the spring 11. A portion of the roller 9' near the bearing 8 passesthrough a coil 3 which is fixedly mounted on the frame 4 and whosecentral opening is shaped to permit the pressure roller 9' to be swungcounterclockwise from the illustrated position for changing the tape 5,and for similar operations.

The modified embodiment of the invention permits the use of a motor 1which rotates at a speed much higher than the desired rotary speed ofthe drive roller 7. Its mode of operation is otherwise closely similarto that of the first-described roller drive.

Many other modifications and variations of the roller drive of theinvention will readily suggest themselves to those skilled in the art onthe basis of the above teachings. It is therefore to be understood that,within the scope of the. appended claims, the invention may be practicedotherwise than as specifically disclosed.

What is claimed is:

1. A roller drive comprising, in combination:

(a) a support;

(b) first and second bearing means mounted on said support for movementrelative to each other, said bearing means respectively having a firstaxis and a second axis;

(c) first and second roller means,

(1) each roller means having a journal portion received in said firstand second bearing means respectively for rotation about said axes; acontact portion having an exposed contact face about the associatedaxis; and another portion,

(2) said three portions of each roller means being spaced in thedirection of the associated axes, and

(3) said first roller means having a fourth portion axially interposedbetween said contact portion and said other portion thereof,

(4) said faces of said contact portions moving toward and away from atape engaging position during said relative movement of said bearingmeans, said faces being spacedly adjacent each other when in saidposition thereof;

V (d) magnetizable means interposed between said other portions of saidroller means to constitute with said roller means a magnetic circuithaving a gap between said contact faces;

(e) conductive coil means mounted on said support and covering saidfourth position of said first roller means for inducing magnetic flux insaid circuit when electric current is passed through said coil means;and

(f) actuating means for actuating rotation of one of said roller means.

2. A drive as set forth in claim 1, wherein said magnetizable meansinclude a flywheel mounted on said one roller means for rotationtherewith about the associated axis, said flywheel having a face portionradially spaced from the last-mentioned axis and adjacent the otherportion of the other roller means.

3. A drive as set forth in claim 1, further comprising yieldablyresilient means urging said contact portions to move into apredetermined inoperative position in which said contact faces arefarther removed from each other than in said tape engaging position.

4. A roller drive comprising, in combination:

(a) a support;

(b) two hearings on said support having respective axes;

(c) yieldably resilient means engaging one of said bearings forangularly moving said axes relative to each other toward a predeterminedposition;

(d) two roller means, each roller means having a journal portionreceived in an associated one of said bearings for rotation about theaxis of the receiving bearing, and two axially spaced portions outsidesaid bearing, one of said spaced portions having a contact face aboutthe associated axis in spaced radial alignment with a correspondingcontact face on the other roller means when said axes are in saidpredetermined position, said contact faces defining a gap therebetween;

(e) a coil substantially coaxially covering a portion of one of saidroller means axially intermediate said spaced portions thereof, saidcoil being energizable by electric current to induce magnetic flux insaid one roller means;

(f) magnetic circuit closing means interposedbetween said portions ofsaid two roller means axially spaced from said portions having saidcontact faces for sequential axial passage of said flux through saidroller means between said spaced portions and through said gap; and

(g) actuating means for actuating said rotation of one of said rollermeans.

5. A drive as set forth in claim 4, wherein at least said spacedportions of said roller means and the portions thereof axiallyconnecting said spaced portions are of magnetizable material.

6. A roller drive comprising, in combination:

(a) a support; 1

(b) a first bearing mounted on said support and having a fixed axis;

(c) a second bearing having a second axis and mounted on said supportfor angular movement of said second axis toward and away from said firstaxis;

(d) first roller means and second roller means, each roller means havinga journal portion received in the corresponding one of said bearings forrotation about the corresponding axis, and a pair of axially terminalportions spaced from said journal portion in opposite axial directions,one member of each pair having a contact face about the associated axisin radial alignment With'the contact face on the other roller means,said roller means being of magnetizablematerial, and said contact facesdefining a first (e) a flywheel of magnetizable material on the othermember of said pair of terminal portions of said first roller means,said flywheel having a radially extending face intersecting said secondaxis and defining a second gap with the other member of said pair ofterminal portions of said second roller means; (f) a conductive coilsubstantially coaxially covering an axial portion of one of said rollermeans intermediate said pair of terminal portions of said one rollermeans; and

(g) actuating means for actuating rotation of said flywheel about saidfirst axis.

7. A drive as set forth in claim 6, wherein said coil is fixedly mountedon said support, and said one roller means rotatably passes through saidcoil.

8. A drive as set forth in claim 7, wherein said one roller means issaid first roller means.

9. A drive as set forth in claim 7, wherein said one roller means issaid second roller means.

References Cited by the Examiner UNITED STATES PATENTS 2,204,887 6/1940' Dewan 226-187 3,197,105 7/1965 Peters 226176 3,227,344 1/1966Rutter 226176 3,279,668 10/ 1966 Fleishcher 226180 M. HE-NSON WOOD, JR.,Primary Examiner.

A. N. KNOWLES, Assistant Examiner.

1. A ROLLER DRIVE COMPRISING, IN COMBINATION: (A) A SUPPORT; (B) FIRSTAND SECOND BEARING MEANS MOUNTED ON SAID SUPPORT FOR MOVEMENT RELATIVETO EACH OTHER, SAID BEARING MEANS RESPECTIVELY HAVING A FIRST AXIS AND ASECOND AXIS; (C) FIRST AND SECOND ROLLER MEANS, (1) EACH ROLLER MEANSHAVING A JOURNAL PORTION RECEIVED IN SAID FIRST AND SECOND BEARING MEANSRESPECTIVELY FOR ROTATION ABOUT SAID AXES; A CONTACT PORTION HAVING ANEXPOSED CONTACT FACE ABOUT THE ASSOCIATED AXIS; AND ANOTHER PORTION, (2)SAID THREE PORTIONS OF EACH ROLLER MEANS BEING SPACED IN THE DIRECTIONOF THE ASSOCIATED AXES, AND (3) SAID FIRST ROLLER MEANS HAVING A FOURTHPORTION AXIALLY INTERPOSED BETWEEN SAID CONTACT PORTION AND SAID OTHERPORTION THEREOF, (4) SAID FACES OF SAID CONTACT PORTIONS MOVING TOWARDAND AWAY FROM A TAPE ENGAGING POSITION DURING SAID RELATIVE MOVEMENT OFSAID BEARING MEANS, SAID FACES BEING SPACEDLY ADJACENT EACH OTHER WHENIN SAID POSITION THEREOF; (D) MAGNETIZABLE MEANS INTERPOSED BETWEEN SAIDOTHER PORTIONS OF SAID ROLLER MEANS TO CONSTITUTE WITH SAID ROLLER MEANSA MAGNETIC CIRCUIT HAVING A GAP BETWEEN SAID CONTACT FACES; (E)CONDUCTIVE COIL MEANS MOUNTED ON SAID SUPPORT AND COVERING SAID FOURTHPOSITION OF SAID FIRST ROLLER MEANS FOR INDUCING MAGNETIC FLUX IN SAIDCIRCUIT WHEN ELECTRIC CURRENT IS PASSED THROUGH SAID COIL MEANS; AND (F)ACTUATING MEANS FOR ACTUATING ROTATION OF ONE OF SAID ROLLER MEANS.